Computrace determines iron content in boiler water

The Metrohm 797 VA Computrace is able to detect trace levels of iron in power station boiler waters.

Iron in power station boiler waters can be a common problem when dark-coloured deposits are formed.

Iron deposits in large amounts can inhibit the heat transfer – making the process less efficient – as well as causing corrosion problems.

In the presence of dissolved oxygen any corrosion on the boiler tubing is intensified, which may necessitate the system coming offline for essential maintenance.

The iron (and its deposits) can easily and reliably be measured in boiler waters using the voltammetry technique.

The 797 VA Computrace from Metrohm is a modern voltammetric measuring instrument that connects to a PC directly via a USB connection.

The Windows XP-based PC software controls the measurement, records the measuring data and allows full evaluation of the recorded information.

The boiler water sample and auxiliary solutions were added to the reaction vessel and the iron determined using adsorptive stripping voltammetry with the Metrohm Multi Mode Electrode (MME).

A typical sample from a UK-based power station was analysed and found to contain 3.6ug l-1 of iron, demonstrating the sensitivity of voltammetry for a fraction of the purchase and the running costs of spectroscopic techniques.

Calibration is performed on each and every sample using standard addition, which takes into account any background matrix effects.

To enhance the accuracy and improve the sample throughput, the technique can be automated using Metrohm Dosinos (for the addition of the standard solutions) and a choice of auto samplers.